Image pickup apparatus and video recording and reproduction system

ABSTRACT

A light ray output from a subject is separated into left and right light rays by mirrors in an area in which a diverging light ray output from a point of the subject is converted into a parallel light ray. When a subject is looked at from the right side or the left side, the light rays are reflected by various mirrors. The light rays reflected by the mirrors are made incident on image forming lenses. These light rays form an image on a light receiving surface of an imaging device. In this way, a high-quality 3D image having an appropriate parallax level and a small chromatic aberration is captured.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a national phase application based onPCT/JP2009/064826, filed Aug. 26, 2009, which claims the priority ofJapanese Patent Application Nos. 2008-221060, filed Aug. 29, 2008 and2009-176212, filed Jul. 29, 2009, the contents of all of which areincorporated herein by reference.

TECHNICAL FIELD

The present invention relates to an image pickup apparatus and a videorecording and reproduction system and, in particular, to an image pickupapparatus and a video recording and reproduction system that capture animage of a subject in the form of a 3D image.

BACKGROUND ART

A system that displays a 3D image by capturing the image of the samesubject using two video cameras disposed in the left and right sides andoutputting the left and right images at the same time has beendeveloped. However, if such two video cameras are used, the size of anapparatus including the cameras is increased and, therefore, theapparatus is not practical. Additionally, in general, the baselineextending between the two cameras, that is, a distance between two eyesof the 3D camera is set to about 65 mm, which corresponds to thedistance between the eyes of a person. In such a case, the parallax isincreased when a zooming operation is performed on the video image, andthe human eye system is forced to perform information processing that isnot performed as usual. Accordingly, eye fatigue occurs. In addition, ifthe right and left images are directly overlaid and are looked at, theimage is doubly-blurred and, therefore, an unnatural video is generated.Note that L and R represent the positions of the two eyes, and A and Brepresent points on the subject. Then, angles LAR and LBR are defined asabsolute parallaxes, and (angle LAR-angle LBR) is defined as a relativeparallax of the point A to the point B. Hereinafter, the term “relativeparallax” is simply referred to as “parallax”.

Therefore, a prism 3D camera that separates a light ray output from asubject and captured by a single video camera into left and right raysusing a prism has been developed (refer to, for example, Patent Document1).

PRIOR ART REFERENCES Patent Document

Patent Document 1: Japanese Unexamined Patent Application PublicationNo. 5-7374 (FIG. 1).

DISCLOSURE OF INVENTION Problems to be Solved by the Invention

In the above-described existing technique, a prism is disposed in frontof a lens of a single video camera, and a light ray is separated intotwo light rays having a parallax in the left-right direction withrespect to the optical axis. However, in such prism 3D cameras, alight-shielding mask needs to be formed on the prism in order to removean overlapping portion of the left and right images. Accordingly,control performed when a 3D image is captured is complicated. Inaddition, a prism uses refraction of an optical axis, and the index ofrefraction varies in accordance with the wavelength of a light ray.Accordingly, chromatic aberration occurs, which is problematic.Furthermore, in the above-described existing technique, the optical pathis bent in an area other than an area in which the light ray isconverted into a parallel light ray in a path from an optical system toan imaging device. Accordingly, when a zoom operation of animage-capturing lens is performed, the optical axis is changed inaccordance with the zoom ratio. As a result, each of the positions ofimages formed on two imaging devices is moved, which is problematic.

Accordingly, it is an object of the present invention to capture ahigh-quality 3D image having an appropriate parallax level and a smallchromatic aberration.

Means for Solving the Problems

To solve the above-described problems, according to a first aspect ofthe present invention, an image pickup apparatus includes animage-capturing lens configured to collect a light ray output from asubject, a relay lens configured to transmit the collected light ray, anaperture configured to control an amount of the transmitted light in anarea in which a diverging light ray output from a point of the subjectis converted into a parallel light ray, a mirror configured to separate,into left and right rays, the light ray having the amount of lightcontrolled in the area in which a diverging light ray output from apoint of the subject is converted into a parallel light ray, twoimage-forming lenses configured to form images from the separate lightrays, and two imaging devices configured to convert the light raysforming the images into images in the form of electronic signals. Inthis way, a light ray collected by a single image capturing lens isseparated by a mirror, and a high-quality 3D image having an appropriateparallax level and a small chromatic aberration is advantageouslycaptured. In addition, the optical axis is not practically changed inaccordance with the zoom ratio of the image capturing lens. Accordingly,image processing, such as moving the position of an image in accordancewith the zoom ratio, is not needed and, therefore, a high-precision zoomeffect can be easily obtained.

In addition, in the first aspect, the aperture may control the amount ofthe transmitted light so as to change a distance between optical axes ofthe two separate light rays. That is, by controlling the amount of lightusing the aperture, a distance between optical axes of the two separatelight rays can be changed.

In addition, in the first aspect, the aperture may control the amount ofthe transmitted light so that a distance between optical axes of the twoseparate light rays ranges from about 7 to about 65 millimeters. Thatis, by adjusting the amount of light using the aperture, a distancebetween the optical axes of the separate light rays can be changed so asto range from about 7 to about 65 millimeters.

In addition, in the first aspect, the image-capturing lens includes azoom lens that enlarges the light ray output from the subject, and arelative parallax between the two images converted by the imagingdevices may be controlled by the zoom lens. In this way, the relativeparallax between the images can be controlled by the zoom lens.

In addition, in the first aspect, each of the plurality of imagingdevices may generate captured images from the electronic signals at arate of 60 frames per second or higher. It is desirable that each of theplurality of imaging devices generate captured images from theelectronic signals at a rate ranging from 230 to 250 frames per second.In this way, the occurrence of blur and jerkiness caused by motion canbe prevented. In addition, for a moving subject, a sufficient timeresolution can be provided, and correct outline information can becaptured.

Furthermore, according to a second aspect of the present invention, avideo recording and reproduction system is provided. The video recordingand reproduction system includes an image-capturing lens configured tocollect a light ray output from a subject, a relay lens configured totransmit the collected light ray, an aperture configured to control anamount of the transmitted light in an area in which a diverging lightray output from a point of the subject is converted into a parallellight ray, a mirror configured to separate, into left and right rays,the light ray having the amount of light controlled in the area in whicha diverging light ray output from a point of the subject is convertedinto a parallel light ray, two image-forming lenses configured to formimages from the separate light rays, two imaging devices configured toconvert the light rays forming the images into images in the form ofelectronic signals, a video recording unit configured to record theimages converted by the two imaging devices in a storage unit in theform of left and right video data frames, and a video reproduction unitconfigured to reproduce and display the left and right video datarecorded in the storage unit at the same time. In this way, a light raycollected by a single image-capturing lens can be separated intoseparate light rays by the mirror, and a high-quality 3D image having anappropriate parallax level and a small chromatic aberration can berecorded and reproduced.

Advantageous Effects

According to the present invention, a 3D image having an appropriateparallax level and a small chromatic aberration can be advantageouslycaptured.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a top cross-sectional view of an exemplary image pickupapparatus according to an embodiment of the present invention.

FIG. 2 illustrates a main portion of the exemplary image pickupapparatus according to the embodiment of the present invention.

FIG. 3 illustrates an image of an entrance pupil 115 of the image pickupapparatus according to the embodiment of the present invention.

FIG. 4 illustrates a relationship between an inter-centroid distance andthe baseline.

FIG. 5 illustrates a relationship between enlargement by zooming andparallax.

FIG. 6 illustrates an example configuration of a video recording andreproduction system according to an embodiment of the present invention.

BEST MODES FOR CARRYING OUT THE INVENTION

Embodiments of the present invention (hereinafter referred to as“embodiments”) are described below. The descriptions will be made in thefollowing order:

1. First Embodiment (Example of Image Pickup Apparatus)

2. Second Embodiment (Example of Video Recording and ReproductionApparatus)

1. First Embodiment Example of Configuration of Image Pickup Apparatus

FIG. 1 is a top cross-sectional view of an exemplary image pickupapparatus according to an embodiment of the present invention. The imagepickup apparatus receives an incident light ray 101 and forms an imageon each of a left imaging device 171 and a right imaging device 172.Thus, the image pickup apparatus generates left video data and rightvideo image data. When the image pickup apparatus faces a subject, theupper section of the drawing is located on the side in the rightdirection (R) whereas the lower section is located on the side in theleft direction (L).

An interchangeable lens 110 can be mounted on the body of the imagepickup apparatus via a lens mount 120. The interchangeable lens 110represents a lens unit that collects the incident light ray 101 outputfrom a subject. The interchangeable lens 110 includes a lens unitincluding a focus lens to capture an image in focus and a zoom lens forenlarging the image of the subject. The interchangeable lens 110 furtherincludes an aperture 113 for the interchangeable lens 110. Note that theinterchangeable lens 110 is an example of an image-capturing lensdefined in the claims.

The lens mount 120 is used to mount the interchangeable lens 110 on thebody of the image pickup apparatus. The collected light ray temporarilyforms an image inside the lens mount 120. The formed image is aninverted image and a mirror-reversed image.

A relay lens unit 130 is disposed downstream of the lens mount 120. Therelay lens unit 130 includes a relay lens that relays the light raycollected in the lens mount 120 to the position of an aperture 149.Through the relay lens, the diverging light ray output from a pointlight source located at the objective focal point is converted into aparallel light ray at the position of the aperture 149. Note that therelay lens unit 130 is an example of a relay lens defined in the claims.

Mirrors 141 to 144 are disposed downstream of the relay lens unit 130.The mirrors 141 to 144 are located at the position of the aperture 149.The mirrors 141 to 144 serve as a beam splitter that separates thecollected light ray into left and right light rays. That is, when thesubject is looked at from the left side, the light ray ismirror-reversed and is reflected by the mirrors 141 and 142. When thesubject is looked at from the right side, the light ray ismirror-reversed and is reflected by the mirrors 143 and 144. Thus, thecollected light ray is separated into the left and right rays. Themirrors 141 to 144 are disposed in an area in which the diverging lightray output from the point light source located at the objective focalpoint (the position of the subject) is converted into a parallel lightray in the lens mount 120. Thus, the light ray is appropriatelyseparated. Note that the aperture 149 is an example of an aperturedefined in the claims.

The light rays separated by the mirrors 141 to 144 are input to imageforming lenses 151 and 152. That is, when the subject is looked at fromthe left side, the light ray separated by the mirrors 141 and 142 isinput to the image forming lens 151. When the subject is looked at fromthe right side, the light ray separated by the mirrors 143 and 144 isinput to the image forming lens 152. The image forming lenses 151 and152 form images from the input light rays on the light receivingsurfaces of the imaging devices 171 and 172, respectively. The lightrays input to the imaging devices 171 and 172 form erected images.

The imaging devices 171 and 172 are photoelectric transducers thatconvert light rays input from the image forming lenses 151 and 152 toelectronic signals, respectively. For example, the imaging devices 171and 172 are realized by CCDs (Charge Coupled Devices) or CMOS(Complementary Metal Oxide Semiconductor) image sensors.

In this way, according to the embodiment of the present invention, theimage pickup apparatus receives the incident light ray 101 output from asubject and separates the incident light ray 101 into left and rightlight rays using the mirrors 141 to 144. Thus, the image pickupapparatus forms images of left and right video data on the left andright imaging devices 171 and 172.

FIG. 2 illustrates the main portion of the exemplary image pickupapparatus according to the embodiment of the present invention. Thelight ray transmitted by the relay lens unit 130 is separated into leftand right light rays by the mirrors 141 and 143. When a subject islooked at from the left side of the subject, the light ray is reflectedby the mirror 141 and is further reflected by the mirror 142. When asubject is looked at from the right side of the subject, the light rayis reflected by the mirror 143 and is further reflected by the mirror144. These mirrors 141 to 144 are disposed at the position of theaperture 149. The incident light ray is converted into a parallel lightray.

The left light ray reflected by the mirror 142 is made incident on theimage forming lens 151. The light ray incident on the image forming lens151 forms an image on the light receiving surface of the imaging device171. The right light ray reflected by the mirror 144 is made incident onthe image forming lens 152. The light ray made incident on the imageforming lens 152 forms an image on the light receiving surface of theimaging device 172.

[Separation of Entrance Pupil]

FIG. 3 illustrates an image of an entrance pupil 115 of the image pickupapparatus according to the embodiment of the present invention. The term“entrance pupil” refers to the image of an aperture stop when a lens islooked at from a subject side. In the image pickup apparatus accordingto the embodiment of the present invention, the image of the aperture113 is present at a position inside the interchangeable lens 110 so asto serve as the entrance pupil 115. Here, let r denote the radius of acircle corresponding to the entrance pupil 115. Then, the followingequation is obtained:2r=f/F  (equation 1)where f represents the focal length, and F represents the F number.Accordingly, it can be found that if the focal length is constant, thediameter 2r of the entrance pupil 115 is inversely proportional to the Fnumber.

According to the embodiment of the present invention, the collectedlight ray is separated into the left and right rays at the position ofthe aperture 149. Therefore, a left semicircle and a right semicirclegenerated by separating the circle of the entrance pupil 115 into theleft and right sections are discussed below. As described above, a 3Deffect can be achieved by the parallax (the relative parallax) of thetwo eyes. At that time, the optical axis that determines the parallaxpasses through centroids of the left and right semicircles. The centroidof the semicircle having a radius of r can be geometrically obtained,and the centroid is located at a distance of 4r/3π from the center ofthe circle. Accordingly, the distance between a centroid 501 of the leftsemicircle and a centroid 502 of the right semicircle (an inter-centroiddistance D) can be expressed as follows:D=8r/3π  (equation 2)That is, it can be found that as the aperture 149 is stopped down, theinter-centroid distance D decreases in proportion to the value of theaperture 149. In other words, by changing the diameter of the aperture149, the 3D effect can be controlled. The result of an experimentconducted to confirm such hypothesis is described below.[Relationship Between Inter-Centroid Distance and Baseline]

FIG. 4 illustrates a relationship between the inter-centroid distanceand the baseline. In this description, the theoretical values of theinter-centroid distances and the experimental values of the baselinesare shown for two types of interchangeable lens 110 #A and #B.

A lens #A is a zoom lens having a full-aperture F value of 1.8 and afocal length of 10 to 100 [mm (millimeter)]. The zoom ratio of the lens#A is 10. The focal length at the wide angle end is 10 [mm]. A lens #Bis a zoom lens having a full-aperture F value of 2.8 and a focal lengthof 13.5 to 570 [mm]. The zoom ratio of the lens #B is 42. The focallength at the wide angle end is 13.5 [mm]. The camera-to-subjectdistance for the two lenses is set to 6.5 [m (meter)].

Using the above-described equation (1) and equation (2), theinter-centroid distances D of the lens #A and #B are 23.6 [mm] and 15.2[mm], respectively. On the other hand, the baselines of the lenses #Aand #B obtained by the experiment using an actual apparatus were 20.0[mm] and 12.0 [mm], respectively. As can be seen from the result of theexperiment, the inter-centroid distance D between the semicircles of theentrance pupil, which is the image of the aperture 113, is substantiallythe same as the baseline, although the value is smaller than thetheoretical value due to, presumably, the effect of diffraction. Inaddition, equation (2) indicates that the inter-centroid distance D canbe changed by changing the diameter of the aperture 149 and, therefore,the baseline can be controlled by changing the diameter of the aperture149.

According to the configuration of the embodiment of the presentinvention, the minimum value of the inter-centroid distance D can beabout 7 [mm]. If the baseline has substantially the same value, a 3Deffect can be provided. In particular, when the camera-to-subjectdistance is long, the 3D effect cannot be provided unless the length ofthe baseline is longer than a certain level. As the baseline isincreased, the 3D effect becomes clearer when the baseline is about 32[mm]. In contrast, the background becomes more blurred. In addition, ifthe baseline exceeds 65 [mm], a puppet theater effect occurs and,therefore, an unnatural image is generated. Accordingly, the range ofthe baseline in which a 3D image can be seen as a natural image is fromabout 7 to about 65 [mm].

[Relationship Between Enlargement by Zooming and Parallax]

FIG. 5 illustrates a relationship between enlargement by zooming andparallax. In FIG. 5( a), L represents the position of the left eye, Rrepresents the position of the right eye, and A and B represent pointsof the subject. When an angle of vergence θ_(A) of the point A isdefined by an angle LAR formed by viewing the point A and an angle ofvergence θ_(B) of the point B is defined by an angle LBR formed byviewing the point A, the parallax (relative parallax) d between thepoints A and B is given by the following equation:d=θ _(B)−θ_(A)Let h denote the angle ALB, and let g denote the angle ARB. Then, theangle of vergence θ_(A) is substantially the same as h, and the angle ofvergence θ_(B) is substantially the same as g. Therefore, the followingequation can be obtained:d=g−h

In addition, let D denote the distance between the two eyes, let D_(A)denote the distance between the point A and the two eyes, let D_(B)denote the distance between the point B and the two eyes, and let δdenote the distance between the points A and B when viewed by two eyes.Then, the following expressions can be obtained:d≅Dδ/(D _(A) ² −δD _(A))Since D_(A), D_(B)>>D, the following expression can be obtained:d≅Dδ/D _(A) ²

FIG. 5( b) illustrates the positional relationship when that in FIG. 5(a) is enlarged n times. In FIG. 5( b), a dash is appended to the symbolsif the angles, the positions, and distances are changed after zooming isperformed. Since the image is enlarged n times, the following equationsare obtained:g′=ng, andh′=nh.At that time, a parallax d′ is expressed as follows:

$\begin{matrix}{d^{\prime} = {\theta_{B}^{\prime} - \theta_{A}^{\prime}}} \\{= {g^{\prime} - h^{\prime}}} \\{= {n\left( {g - h} \right)}} \\{= {nd}}\end{matrix}$

That is, by enlarging the image n times, a parallax of n times theoriginal parallax occurs. This means that as a zooming operation isperformed towards a telephoto end, a 3D effect increases. In otherwords, in zooming image capturing, a proper parallax can be obtainedeven in the case of a short baseline.

As described above, according to the first embodiment of the presentinvention, by separating a light ray collected by the singleinterchangeable lens 110 into left and right rays using the mirrors 141to 144, the parallax of an image presented to the two eyes can beproperly reduced. The parallax obtained in the embodiment of the presentinvention can be controlled by adjusting the diameter of the aperture149 and the zoom ratio (the magnification factor) used during a zoomimage capturing operation. In general, the sensitivity of the eyes toparallax is significantly high. The normal visual acuity of the eyes isan order of a minute, whereas the parallax acuity is higher than thenormal visual acuity by one order (Howard I. P., Rogers B. J.: StereoAcuity (Chap. 5), Binocular Vision and Stereopsis, p. 162, OxfordUniversity Press, Oxford (1995).) Accordingly, in order to naturallyperceive a 3D effect and reduce eye fatigue, it is important to properlyreduce the parallax even under the condition in which the parallax issmaller than that in the above-described example.

2. Second Embodiment Exemplary Configuration of Video Recording andReproduction System

FIG. 6 illustrates an example configuration of a video recording andreproduction system according to an embodiment of the present invention.The video recording and reproduction system includes an image pickupunit 100, a video recording unit 200, and a video storage unit 300, anda video reproduction unit 400, and a display unit 500.

The image pickup unit 100 corresponds to the above-described imagepickup apparatus. The image pickup unit 100 receives an incident lightray output from a subject and generates the left and right video datausing a left imaging device 171 and a right imaging device 172.

The video recording unit 200 records the left and right video dataoutput from the image pickup unit 100 in the video storage unit 300. Thevideo recording unit 200 includes signal processing units 211 and 212,image memories 221 and 222, and encoding units 231 and 232, whichcorrespond to the left and right data, respectively. The signalprocessing units 211 and 212 receive the left and right video dataoutput from the image pickup unit 100, respectively, and performpredetermined signal processing on the video data. The signal processingunits 211 and 212 perform A/D (Analog to Digital) conversion on thevideo data and correct the white balance. The image memories 221 and 222are memories that temporarily store the video data processed by thesignal processing units 211 and 212, respectively. The encoding units231 and 232 encode the video data stored in the image memories 221 and222, respectively, and output the encoded video data to the videostorage unit 300.

The video storage unit 300 stores the left and right video data outputfrom the video recording unit 200. The video data stored in the videostorage unit 300 is read by the video reproduction unit 400.

The video reproduction unit 400 reads out the video data stored in thevideo storage unit 300 and reproduces the video data. The videoreproduction unit 400 includes decoding units 411 and 412 and displaycontrol units 421 and 422 corresponding to the left and right videodata. The decoding units 411 and 412 decode the left and right videodata read from the video storage unit 300, respectively. The displaycontrol units 421 and 422 perform control so that the left and rightvideo data decoded by the decoding units 411 and 412, respectively, aredisplayed on the display unit 500.

The display unit 500 displays the left and right video data output fromthe video reproduction unit 400. For example, the display unit 500 has aconfiguration in which two projectors having circularly or linearlypolarized filters attached thereto display two images for the left andright eyes, and the user views the images through circularly or linearlypolarized glasses. Alternatively, a flat panel display with a filter maysimilarly display two images for the left and right eyes at the sametime, and the user may view the images using a 3D display unit of alenticular lens method or a parallax barrier method without usingglasses. In this way, according to the embodiment of the presentinvention, by displaying the left and right images at the same timeinstead of alternately displaying the left and right images, eye fatiguecan be reduced.

Furthermore, according to the embodiment of the present invention, byemploying a high frame rate from when video data is generated by theimage pickup unit 100 to when the video data is displayed by the displayunit 500, blur and jerkiness of an image caused by a motion can beprevented. Motion blur is frequently caused by reduction in an MTF(Modulation Transfer Function) and, in particular, by slipping of avideo image on the retina occurring when a moving subject is viewedwhile following the subject on a device performing hold-type display(i.e., visual tracking). As used herein, the term “hold-type display”refers to a display state in which video is continuously displayed usinga film or a liquid crystal projector during a frame period. In addition,the term “jerkiness” refers to loss of smoothness of video motion andthe occurrence of jerky video motion. Jerkiness frequently occurs whenvideo captured using a high shutter speed is viewed with a fixed line ofsight (i.e., fixed viewing). Such degradation of the quality of a movingimage is related to the frame rates of image capturing and imagedisplaying, the aperture ratio (aperture time/frame time) of the camerawhen an image is captured, and visual features.

In general, 24 frames per second (24 Hz) are used for movies, and 60fields per second (60 Hz) are used for television programs as a framerate. According to the embodiment of the present invention, in order toreduce blur and jerkiness caused by motion, a captured image isgenerated from an electronic signal at a rate of 60 frames per second(60 Hz) or higher and, more preferably, 230 to 250 frames per second(240 Hz±10 Hz). In this way, a problem of an insufficient resolution inthe time direction is solved.

As described above, according to the second embodiment of the presentinvention, by setting the parallax of an images presented to the twoeyes to a proper level and employing a high frame rate, a high-quality3D image that can be easily viewed in the same way a user looks at thenatural world and that has low aberration can be captured. In addition,the optical axis is not practically changed by the zoom ratio and,therefore, image processing, such as moving the position of an image inaccordance with the zoom ratio, is not required. Thus, high-precisionzoom effect can be easily obtained.

Note that the embodiments of the present invention are only examples forillustrating the present invention. As described in the embodiments ofthe present invention, there is a correspondence between an element ofthe embodiments of the present invention and an element of the inventiondefined in the claims. Similarly, there is a correspondence between anelement of the invention defined in the claims and an element and anelement of the embodiments of the present invention having the samename. However, it is to be understood that the invention is not limitedto the disclosed exemplary embodiments. The present invention can bepracticed with various modifications within the spirit and scope of theinvention.

EXPLANATION OF REFERENCE NUMERALS

-   -   100 image pickup unit, 101 incident light ray, 110        interchangeable lens, 120 lens mount, 130 relay lens unit,        141-144 mirror, 151, 152 image forming lens, 171, 172 imaging        device, 200 video recording unit, 211, 212 signal processing        unit, 221, 222 image memory, 231, 232 encoding unit, 300 video        storage unit, 400 video reproduction unit, 411, 412 decoding        unit, 421, 422 display control unit, 500 display unit

The invention claimed is:
 1. An image pickup apparatus comprising: animage-capturing lens configured to collect a light ray output from asubject, the image-capturing lens comprising: a focus lens; a zoom lensdisposed downstream from the focus lens; and a first aperture disposedbetween the focus lens and the zoom lens, the focus lens and the zoomlens being configured to generate an image of the first aperture thatserves as an entrance pupil located at a position inside the imagecapturing lens; a relay lens configured to transmit the collected lightray; a second aperture configured to control an amount of thetransmitted light in an area in which a diverging light ray output froma point of the subject is converted into a parallel light ray; a mirrorconfigured to separate, into left and right rays, the light ray havingthe amount of light controlled in the area in which a diverging lightray output from a point of the subject is converted into a parallellight ray; two image-forming lenses configured to form images from theleft and right light rays; and two image devices configured to convertthe light rays forming the images into electronic signals representingthe images.
 2. The image pickup apparatus according to claim 1, whereinthe second aperture controls the amount of the transmitted light so asto change a distance between optical axes of the two separate lightrays.
 3. The image pickup apparatus according to claim 1, wherein thesecond aperture controls the amount of the transmitted light so that adistance between optical axes of the two separate light rays ranges fromabout 7 to about 65 millimeters.
 4. The image pickup apparatus accordingto claim 1, wherein the zoom lens that enlarges the light ray outputfrom the subject and wherein a relative parallax between the two imagesconverted by the imaging devices is controlled by the zoom lens.
 5. Theimage pickup apparatus according to claim 1, wherein each of theplurality of imaging devices generates captured images from theelectronic signals at a rate of 60 frames per second or higher.
 6. Theimage pickup apparatus according to claim 5, wherein each of theplurality of imaging devices generates captured images from theelectronic signals at a rate between 230 frames per second and 250frames per second.
 7. A video recording and reproduction systemcomprising: an image-capturing lens configured to collect a light rayoutput from a subject, the image-capturing lens comprising: a focuslens; a zoom lens disposed downstream from the focus lens; and a firstaperture disposed between the focus lens and the zoom lens, the focuslens and the zoom lens being configured to generate an image of thefirst aperture that serves as an entrance pupil located at a positioninside the image capturing lens; a relay lens configured to transmit thecollected light ray; a second aperture configured to control an amountof the transmitted light in an area in which a diverging light rayoutput from a point of the subject is converted into a parallel lightray; a mirror configured to separate, into left and right rays, thelight ray having the amount of light controlled in the area in which adiverging light ray output from a point of the subject is converted intoa parallel light ray; two image-forming lenses configured to form imagesfrom the left and right light rays; two imaging devices configured toconvert the light rays forming the images into electronic signalsrepresenting the images; a video recording unit configured to record theelectronic signals in a storage unit in the form of frames of left andright video data; and a video reproduction unit configured to reproduceand simultaneously display the left and right video data recorded in thestorage unit.